1. Field of the Invention
The present invention relates to the field of load or power transmissions and more particularly to a novel variable speed transmission of the friction-drive type having opposing cones with a load translating means interposed therebetween.
2. Brief Description of the Prior Art
A conventional motion transmitting mechanism as is known in the prior art usually comprises a pair of cones, each mounted on a shaft with the cones being oppositely inclined. In order that the intermediate drive member may operate between parallel surfaces, the cone pairs generally have the same cone angle and the shafts are aligned parallel in their mounting. Variation in the speed of rotation of the driven cone relative to the driving cone is obtained by shifting the intermediate drive member so that it bears against a relatively larger or a relatively smaller part of the driven cone. Thus, to increase the speed of rotation of the driven cone relative to the driving cone, the intermediate drive member is moved in the opposite direction. A separate shifting means is usually included to provide the required axial movement of the intermediate drive member. Various arrangements may be used to provide this axial movement such as worm threaded screws, shift bars, or other similar type devices.
Certain disadvantages have been encountered in prior arrangements of this type. These include difficulties in maintaining the proper degree of contact between the several drive components. Slippage of the intermediate member and its driving and driven cones is always present. This adversely affects load transferring and driving efficiency. Moreover, prior mechanisms have experienced difficulties in changing both speed and direction of rotation. Back rotation and slippage are generally experienced in conventional mechanisms.